Among the scientific interests of cancer epidemiology is the identification of both environmental and genetic factors associated with cancer development. Observational designs requiring sophisticated methodology are applied to control for potential confounding factors. The enormous biotechnological potential developed in the last two decades has allowed the integration of a plethora of new biomarkers in epidemiological studies to better define the exposure and "neoclassic" outcomes, as well as incorporating genetic susceptibility factors in both classical and new epidemiological designs. The integration of scopes, objectives, data and tools coming from different disciplines also benefits epidemiology, thus evolving into "systems epidemiology". In this manuscript, we review the basic concepts of study designs and data analysis and introduce readers to the more innovative aspects that are now being applied in epidemiological studies.